Novel photoresist monomer having hydroxy group and carboxy group, copolymer thereof and photoresist composition using the same

ABSTRACT

The present invention relates to novel monomers which can be used to form polymers which are useful in a photolithography employing a light source in the far ultraviolet region of the light spectrum, copolymers thereof, and photoresist compositions prepared therefrom. Photoresist monomers of the present invention are represented by the following Chemical Formula 1:  
                 
 
     wherein,  
     R is substituted or non-substituted linear or branched (C 1 -C 10 ) alkyl, substituted or non-substituted (C 1 -C 10 ) ether, substituted or non-substituted (C 1 -C 10 ) ester, or substituted or non-substituted (C 1 -C 10 ) ketone;  
     X and Y are independently CH 2 , CH 2 CH 2 , oxygen or sulfur; and  
     i is 0 or an integer of 1 to 2.

FIELD OF THE INVENTION

[0001] The present invention relates to novel monomers used forpreparing a photoresist copolymer, copolymers thereof, and photoresistcompositions prepared therefrom. More specifically, it relates to suchnovel monomers, copolymers and photoresist compositions suitable to beexposed to light in the far ultraviolet region of the spectrum.

BACKGROUND OF THE INVENTION

[0002] A photosensitive film for use with far ultraviolet light, inparticular, for ArF radiation, must satisfy several requisites; it musthave low light absorbance at a wavelength of 193 nm, excellent etchingresistance and adhesiveness to a substrate, and be developable in anaqueous solution of 2.38% or 2.6% tetramethylammonium hydroxide(hereinafter, abbreviated as TMAH). Up to the present time, researchershave focused on searching for a substance having as high transparencyand etching resistance at 193 mn as novolac resins. For example,researchers at the Bell Labs Research Center have enhanced etchingresistance of photoresist copolymers by adding an alicyclic unit to themain chain. In addition, researchers at Fujitsu of Japan and Sipri ofthe United States are actively investigating methacrylate and acrylatecompounds as photoresist polymers. However, these techniques have notsolved the problem of etching resistance, and involve increasedproduction costs resulting from the introduction of alicyclic groupsinto the polymer. In addition, the low adhesiveness exhibited by mostprior art photoresists is disadvantageous in that photolithographicpatterns cannot be established with integrated L/S patterns of 150 nm orless.

SUMMARY OF THE INVENTION

[0003] An object of the present invention is to solve the problemsdescribed above, and to provide novel monomers which can be used to formcopolymers which have excellent adhesiveness and sensitivity, and whichcan be easily produced at low production cost, and to provide a processfor preparing the monomers.

[0004] Another object of the present invention is to provide copolymersof the novel monomers, and a process for preparing the same.

[0005] Another object of the present invention is to provide photoresistcompositions using the copolymers and a process for preparing the same.

[0006] Still another object of the present invention is to provide asemiconductor element produced by using the photoresist composition.

[0007] The present invention provides a novel compound represented byfollowing Chemical Formula 1:.

[0008] wherein,

[0009] R is substituted or non-substituted linear or branched (C₁-C₁₀)alkyl, substituted or non-substituted (C₁-C₁₀) ether, substituted ornon-substituted (C₁-C₁₀) ester, or substituted or non-substituted(C₁-C₁₀) ketone;

[0010] X and Y are independently CH₂, CH₂CH₂, oxygen or sulfur; and

[0011] i is 0 or an integer of 1 to 2.

[0012] In order to achieve other technical objects, photoresistcopolymer comprising repeating units of the monomer of Formula 1 areprovided by another embodiment of the present invention. Preferredcopolymers are represented by following Chemical Formulas 100 and 100a:.

[0013] wherein,

[0014] R is substituted or non-substituted linear or branched (C₁-C₁₀)alkyl, substituted or non-substituted (C₁-C₁₀) ether, substituted ornon-substituted (C₁-C₁₀) ester, or substituted or non-substituted(C₁-C₁₀) ketone;

[0015] X, Y, V and W are independently CH₂, CH₂CH₂, oxygen or sulfur;

[0016] i and j are independently 0 or an integer of 1 to 2;

[0017] R* is an acid-reactable group; and

[0018] a, b and c represent the polymerization ratio of the monomers.

[0019] In the case of the chemical formula 100, it is preferred thata:b:c—(0.01-0.2):(0.1-0.4): 0.5 in molar equivalent ratio.

[0020] The photoresist composition according to the present inventioncomprises (i) a photoresist copolymer according to the presentinvention, a photoacid generator and a conventional organic solvent.

[0021] Hereinafter, the present invention will be described in detail.

DETAILED DESCRIPTION

[0022] Compounds of Chemical Formula 1 have been found to beparticularly useful for preparing chemically amplified photoresistcopolymers. Compounds of Chemical Formula 1 have a HYDROXY group whichcan enhance adhesiveness of the photoresist to a wafer substrate and acarboxylic acid group which can contribute to the enhancement ofphoto-sensitivity at the same time. In addition, the compounds can besimply synthesized without toxic odors and are readily crystallized inwater without using any complicated separating means such asdistillation or column chromatography. Thus, compounds of the presentinvention are advantageous in mass production at low cost.

[0023] In preferred compounds of Chemical Formula 1, R is represented bythe following Chemical Formula 1a:

[0024] wherein,

[0025] Z is carbon or oxygen,;

[0026] R₁ and R₂ are independently H or an (C₁-C₅) alkyl; and

[0027] m and n are independently 0 or an integer of 1 to 5.

[0028] The photoresist monomer according to the present invention can beprepared by reacting (i) a di-alcohol such as ethylene glycol,1,3-propanediol, 1,4-butanediol, 1,5-pentanediol,2,2-diethyl-1,3-propanediol, 2,2-dimethyl-1,3-propanediol and diethyleneglycol and (ii) an anhydride such as 5-norbornene-2,3-dicarboxylicanhydride and exo-3,6-epoxy-1,2,3,6-tetrahydrophthalic anhydride, in anorganic solvent such as tetrahydrofuran, dimethylformamide, dioxane,benzene and toluene.

[0029] For example, the compound represented by the following ChemicalFormula 2, one of the compounds represented by the above Formula 1, canbe obtained by reacting a compound of Chemical Formulas 2a and 2b in thepresence of an acid catalyst or a base:

[0030] wherein,

[0031] Y is CH₂, CH₂CH₂, oxygen or sulfur;

[0032] Z is carbon or oxygen;

[0033] R₁ and R₂ are independently H or an (C₁-C₅) alkyl; and

[0034] m and n are independently 0 or an integer of 1 to 5.

[0035] The compound of Chemical Formula 2a may be used in the sameamount or in an excess amount relative to the compound of ChemicalFormula 2b.

[0036] NaH, KH, CaH₂, Na₂CO₃, LDA (lithium diisopropylamide) or the likemay be used as a base, and sulfuric acid, acetic acid or nitric acid maybe used as an acid catalyst.

[0037] Novel monomers according to the present invention (the compoundsrepresented by Chemical Formula 1) can also be prepared by a Diels-Alderreaction.

[0038] For example, the compound represented by the above chemicalformula 2 can be prepared by following Reaction Schemes (1) and (2)below:

[0039] wherein,

[0040] Y is CH₂, CH₂CH₂, oxygen or sulfur;

[0041] Z is carbon or oxygen;

[0042] R₁ and R₂ are independently H or an (C₁-C₅) alkyl; and

[0043] m and n are independently 0 or an integer of 1 to 5.

[0044] That is, first, the intermediate material is obtained by reactingmaleic anhydride and di-alcohol in an organic solvent such as benzene,tetrahydrofuran, dimethylformamide or dioxane in the presence of an acidcatalyst, as shown in the Reaction Scheme 1, and then, the final productmaterial is obtained by a Diels-Alder reaction which is performed in anorganic solvent such as benzene and tetrahydrofuran, as shown in theReaction Scheme 2.

[0045] Preferred photoresist copolymers according to the presentinvention comprise repeating units of a compound of Chemical Formula 1as a first comonomer and a compound of the following Chemical Formula 3as the second comonomer:

[0046] wherein,

[0047] V and W are independently CH₂, CH₂CH₂, oxygen or sulfur;

[0048] j is 0 or an integer of 1 to 2; and

[0049] R* is an acid reactable group.

[0050] In the Chemical Formula 3, the R* is released when it is reactedwith the acid produced by the photoacid generator in the photoresistcomposition. Thus, while the photoresist polymer in exposed regions ofthe photoresist layer becomes soluble in the developing solution, thepolymer in the unexposed regions is not dissolved in the developingsolution because acid is not generated therein and therefore theacid-reactable groups are still bound to the photoresist polymer. As theresult, a predetermined pattern is formed.

[0051] Accordingly, the compounds of Chemical Formula 3 have a role inenhancing the photosensitivity of the photoresist polymer by increasingthe difference in solubility in the developing solution between theexposed portion and the unexposed portion.

[0052] Suitable acid-reactable (acid labile) groups include tert-butyl,2-tetrahydrofuranyl, 2-tetrahydropyranyl, 2-ethoxyethyl, t-butoxyethyland so on. In a most preferred embodiment, the second comonomer istert-butyl-5-norbornene-2-carboxylate, the compound of followingChemical Formula 3a:

[0053] Maleic anhydride or maleimide derivatives can be added aspolymerization-enhancing monomers for making the polymerization betweenthe cycloolefin compounds more efficient. However, when performingpolymerization using a metal catalyst, such a polymerization-enhancingmonomer is not necessarily required.

[0054] The first comonomer of Formula 1 and the second comonomer ofFormula 3 comprising the photoresist copolymer according to the presentinvention each contain substituents having large steric hindrance.Therefore, in preferred copolymers a spacer comonomer, such as thecompound of the following Chemical Formula 4, is added to the mainpolymer chain in order not only to reduce the steric hindrance (thusincreasing the synthetic yield, preferably to over 40%), but also toproperly adjust the molecular weight to a desirable range (preferably,in the range of 7,000-8,000).

[0055] wherein,

[0056] U is CH₂, CH₂CH₂, oxygen or sulfur; and

[0057] R′ is hydrogen or C₁-C₅ alkyl.

[0058] More preferred, the R′ is hydrogen or methyl.

[0059] The following Chemical Formulas 100, 200, 100a and 200a representpreferred photoresist copolymers according to the present invention.

[0060] wherein,

[0061] X, Y, V, W and U are independently CH₂, CH₂CH₂, oxygen or sulfur;

[0062] R is substituted or non-substituted linear or branched (C₁-C₁₀)alkyl, substituted or non-substituted (C₁-C₁₀) ether, substituted ornon-substituted (C₁-C₁₀) ester, or substituted or non-substituted(C₁-C₁₀) ketone;

[0063] R* is an acid-reactable group;

[0064] R′ is hydrogen or C₁-C₅ alkyl;

[0065] i and j are independently 0 or an integer of 1 to 2; and

[0066] a, b, c and d are independently the polymerization ratio of thecomonomers.

[0067] The molecular weight of the photoresist copolymers according theto present invention is 3,000 to 12,000, preferably, 5,000 to 10,000.

[0068] While the copolymers represented by the Chemical Formulas 100 and200 are mainly obtained by a synthesizing method using a polymerizationinitiator, the copolymers represented by the Chemical Formulas 100a and200a are mainly obtained by a synthesizing method using a metalcatalyst.

[0069] A synthesizing method using a polymerization initiator isperformed by reacting the comonomers in an organic solvent in thepresence of a polymerization initiator. Presently preferred organicsolvents include tetrahydrofuran, dimethylformamide, dimethyl sulfoxide,dioxane, methyl ethyl ketone, benzene, toluene or xylene may be used.Conventional radical polymerization initiators, such as2,2-azobisisobutyronitile (AIBN), acetyl peroxide, lauryl peroxide andtert-butyl peroxide may be used in the synthesis of the copolymers ofthe present invention.

[0070] Photoresist compositions according to the present invention,which are useful for photolithography processes employing a deepultraviolet light source such as ArF, may be prepared by dissolving aphotoresist copolymer according to the present invention together with aconventional photoacid generator in a conventional organic solvent.

[0071] Sulfide or onium type compounds are preferably used as thephotoacid generator. The photoacid generator may be one or morecompounds selected from the group consisting of diphenyl iodidehexafluorophosphate, diphenyl iodide hexafluoroarsenate, diphenyliodidehexafluoroantimonate, diphenyl p-methoxyphenyl triflate, diphenylp-toluenyl triflate, diphenyl p-isobutylphenyl triflate, diphenylp-tert-butylphenyl triflate, triphenylsulfonium hexafluorophosphate,triphenylsulfonium hexafluoroarsenate, triphenylsulfoniumhexafluoroantimonate, triphenylsulfonium triflate anddibutylnaphthylsulfonium triflate. The photoacid generator is used in anamount of 0.05 to 10% by weight of the photoresist copolymer employed.If the amount of the photoacid generator is less than 0.05% by weight,photosensitivity of the photoresist becomes poor. On the other hand, ifthe amount is more than 10%, the photoacid generator readily absorbsdeep ultraviolet to provide a pattern having poor cross-sectionalsurface.

[0072] A conventional organic solvent, such as ethyl3-ethoxypriopionate, methyl 3-methoxypropionate, cyclohexanone,propylene glycol methyl ether acetate, or the like, may be used in thephotoresist compositions of the present invention. The amount of solventused is 200 to 1000% by weight of the photoresist copolymer, in order toobtain a photoresist layer of desirable thickness. According to theexperiments by the present inventors, when the amount of solvent is 600%by weight, a photoresist layer having a thickness of 0.5 μm is obtained.

[0073] A conventional photoresist pattern-forming method can be usedwith the photoresist composition prepared according to the presentinvention, for example as follows:

[0074] First, the photoresist composition of the present invention isspin-coated on a silicon wafer to form a thin film, which is thensoft-baked (i.e. heated in an oven or on a hot plate at 70 to 200° C.,preferably at 80 to 150° C. for 1 to 5 minutes), and exposed to light byusing an exposing device employing a deep ultraviolet light source, suchas ArF light and KrF light, which has a wavelength below 250 nm. Then,the wafer is post-baked (i.e. heated at 70 to 200° C., more preferably,100 to 200° C.). Then, the wafer is impregnated in 2.38% aqueous TMAHdeveloping solution for 1.5 minutes, to obtain a photoresist image.

[0075] In the above procedure, the exposure energy is preferably 0.1 to30 mJ/cm² and, instead of the deep ultraviolet light source, an E-beam,X-ray, EUV, VUV(Vacuum Ultra Violet) or similar light source may beused.

[0076] By employing the photoresist composition according to the presentinvention, a line/space (L/S) photoresist pattern having excellentadhesiveness and resolution is obtained, without patten collapse, evenwhen isolation is not more than 70 nm.

[0077] According to the present invention, a photoresist compositionhaving excellent etching resistance and adhesiveness can be manufacturedin large scale with low production cost, and a semiconductor elementhaving excellent reliability can be prepared therefrom.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

[0078] The invention is described in more detail by referring to theexamples below, but it should be noted that the present invention is byno means restricted to such examples.

[0079] Synthesis of Photoresist Monomer

EXAMPLE 1 Synthesis of 5-norbornene-2-carboxylic acid-3-hydroxyethylcarboxylate

[0080] Ethylene glycol (0.1 mole) is added to 100 ml of tetrahydrofuran,and the mixture is chilled to −20° C. The chilled mixture is stirred for20-30 minutes in the presence of a basic catalyst, for example, 0.1 moleof sodium hydride. Then, 0.1 mole of 5-norbornene-2,3-dicarboxylicanhydride is slowly added thereto, and the temperature is raised to roomtemperature to perform the reaction for 24 hours. When the reaction iscompleted, tetrahydrofuran is distilled off, and the residue is mixedwith 0.2 N hydrochloric acid solution (500 ml), and the mixture iscrystallized in a refrigerator for several days. Then, the resultantmaterial is filtered, washed with cold water (100 ml), and dried toobtain the compound of Chemical Formula 11 as a pure a colorless solid(19.4 g/yield: 86%).

[0081] In the process described above, the crystallization step requiresa long time (not less than a week). In order to solve the problem, thematerial resulting from the treatment with hydrochloric acid isextracted with 500 ml of ethyl acetate, dried over a dehydrating agentsuch as anhydrous magnesium sulfate and filtered. After evaporating thefiltrate under reduced pressure, a white solid is obtained, which isthen recrystallized from acetone/petroleum ether to provide the compoundof Chemical Formula 11 in a pure state (17.6 g/yield: 78%).

EXAMPLE 2 Synthesis of 5-norbornene-2-carboxylic acid-3-hydroxypropylcarboxylate

[0082] The procedure of Example 1 is repeated but using 1,3-propanediolinstead of ethylene glycol as a reactant, to obtain the compound ofChemical Formula 12 as a colorless solid (21.1 g/yield: 88%).

EXAMPLE 3 Synthesis of 5-norbornene-2-carboxylic acid-3-hydroxybutylcarboxylate

[0083] The procedure of Example 1 is repeated but using 1,3-butanediolinstead of ethylene glycol as a reactant, to obtain the compound ofChemical Formula 13 as a colorless solid (22.6 g/yield: 89%).

EXAMPLE 4 Synthesis of 5-norbornene-2-carboxylic acid-3-hydroxypentylcarboxylate

[0084] The procedure of Example 1 is repeated but using 1,5-pentanediolinstead of ethylene glycol as a reactant, to obtain the compound ofChemical Formula 14 as a colorless solid (22.8 g/yield: 85%).

EXAMPLE 5 Synthesis of 5-norbornene-2-carboxylicacid-3-(2-ethyl-hydroxymethyl)butyl carboxylate

[0085] The procedure of Example 1 is repeated but using2,2-diethyl-1,3-propanediol instead of ethylene glycol as a reactant, toobtain the compound of Chemical Formula 15 as a colorless solid (26.9g/yield: 91%).

EXAMPLE 6 Synthesis of 5-norbornene-2-carboxylicacid-3-(2,2-dimethyl)hydroxypropyl carboxylate

[0086] The procedure of Example 1 is repeated but using2,2-dimethyl-1,3-propanediol instead of ethylene glycol as a reactant,to obtain the compound of Chemical Formula 16 as a colorless solid (24.1g/yield: 90%).

EXAMPLE 7 Synthesis of 5-norbornene-2-carboxylicacid-3-(2-hydroxyethoxy)ethyl carboxylate

[0087] The procedure of Example 1 is repeated but using diethyleneglycol instead of ethylene glycol as a reactant, to obtain the compoundof Chemical Formula 17 as a colorless solid (19.2 g/yield: 71%).

EXAMPLE 8 Synthesis of oxabicyclo[2.2.1]-hept-5-ene-2-carboxylicacid-3-hydroxyethyl carboxylate

[0088] Ethylene glycol (0.1 mole) is added to 100 ml of tetrahydrofuran,and the mixture is chilled to −20° C. To the chilled mixture, sodiumhydride (0.1 mole) is added, and the resultant mixture is stirred for20-30 minutes. Then, 0.1 mole ofexo-3,6-epoxy-1,2,3,6-tetrahydrophthalic anhydride is slowly addedthereto, and the temperature is raised to room temperature to performthe reaction for 24 hours. When the reaction is completed,tetrahydrofuran is distilled off, and the residue is mixed with 0.2 Nhydrochloric acid solution (500 ml), and the mixture is crystallized ina refrigerator for several days. Then, the resultant material isfiltered, washed with cold water (100 ml), and dried to obtain thecompound of Chemical Formula 18 as a colorless solid (19.4 g/yield:86%).

[0089] In the process for preparing the compound of Chemical Formula 18described above, the crystallization step requires a long time of notless than a week. Thus, in order to solve the problem, the materialresulting from the treatment with hydrochloric acid is extracted with500 ml of ethyl acetate, dried over a dehydrating agent such asanhydrous magnesium sulfate, and filtered. After evaporating thefiltrate under reduced pressure, a white solid is obtained, which isthen recrystallized from acetone/petroleum ether to provide the compoundof Chemical Formula 18 in a pure state (17.6 g/yield: 78%).

EXAMPLE 9 Synthesis of oxabicyclo[2.2.1]hept-5-ene-2-carboxylicacid-3-hydroxypropyl carboxylate

[0090] The procedure of Example 8 is repeated but using 1,3-propanediolinstead of ethylene glycol as a reactant, to obtain the compound ofChemical Formula 19 as a colorless solid (20.8 g/yield: 86%).

EXAMPLE 10 Synthesis of oxabicyclo[2.2.1]hept-5-ene-2-carboxylicacid-3-hydroxybutyl carboxylate

[0091] The procedure of Example 8 is repeated but using 1,4-butanediolinstead of ethylene glycol as a reactant, to obtain the compound ofChemical Formula 20 as a colorless solid (22.3 g/yield: 87%).

EXAMPLE 11 Synthesis of oxabicyclo[2.2.1]hept-5-ene-2-carboxylicacid-3-hydroxypentyl carboxylate

[0092] The procedure of Example 8 is repeated but using 1,5-pentanediolinstead of ethylene glycol as a reactant, to obtain the compound ofChemical Formula 21 as a colorless solid (23.8 g/yield: 88%).

EXAMPLE 12 Synthesis of oxabicyclo[2.2.1]hept-5-ene-2-carboxylicacid-3-(2-ethyl-2-hydroxymethyl)butyl carboxylate

[0093] The procedure of Example 8 is repeated but using2,2-diethyl-1,3-propanediol instead of ethylene glycol as a reactant, toobtain the compound of Chemical Formula 22 as a colorless solid (27.7g/yield: 93%).

EXAMPLE 13 Synthesis of oxabicyclo[2.2.1]hept-5-ene-2-carboxylicacid-3-(2.2-dimethyl)hydroxypropyl carboxylate

[0094] The procedure of Example 8 is repeated but using2,2-dimethyl-1,3-propanediol instead of ethylene glycol as a reactant,to obtain the compound of Chemical Formula 23 as a colorless solid (23.6g/yield: 86%).

EXAMPLE 14 Synthesis of oxabicyclo[2.2.1]hept-5-ene-2-carboxylicacid-3-(2-hydroxyethoxy) ethyl carboxylate

[0095] The procedure of Example 8 is repeated but using diethyleneglycol instead of ethylene glycol as a reactant, to obtain the compoundof Chemical Formula 24 as a colorless solid (21.2 g/yield: 78%).

[0096] Synthesis of Photoresist Copolymer

EXAMPLE 15 Synthesis of poly(5-norbornene-2-carboxylicacid-3-(2.2-diethyl)-hydroxypropyl carboxylate/tert-butyl5-norbornene-2-carboxylate/maleic anhydride)

[0097] 5-norbornene-2-carboxylic acid-3-(2,2-diethyl)-hydroxypropylcarboxylate(0.2 mole), tert-butyl 5-norbornene-2-carboxylate(0.8 mole)and maleic anhydride (1.0 mole) are dissolved in tetrahydrofuran. Then,0.5 to 10 g of AIBN (azobisisobutyronitrile) as a polymerizationinitiator is added thereto, and the resultant mixture is reacted atabout 60-70° C. for 4 to 24 hours under nitrogen or argon atmosphere.

[0098] The polymer thus obtained is precipitated from ethyl ether orhexane, and dried to obtain the following compound of Chemical formula101 (yield: 39%).

EXAMPLE 16 Synthesis of poly(mono-2-ethyl-2-hydroxymethylbutylbicyclo[2,2,2]oct-5-ene-2,3-dicarboxylate/tert-butyl5-norbornene-2-carboxylate/maleic anhydride)

[0099] The procedure of Example 15 is repeated but usingmono-2-ethyl-2-hydroxymethylbutylbicyclo[2,2,2]oct-5-ene-2,3-dicarboxylate (0.2 mole) instead of5-norbornene-2-carboxylic acid-3-(2,2-diethyl)-hydroxypropyl carboxylate(0.2 mole), to obtain the compound represented by the following ChemicalFormula 102. (yield: 36%).

EXAMPLE 17 Synthesis of poly(5-norbornene-2-carboxylicacid-3-(2,2-diethyl)-hydroxypropyl carboxylate/tert-butylbicyclo[2,2,2]oct-5-endo-2-carboxylate/maleic anhydride)

[0100] The procedure of Example 15 is repeated but using tert-butylbicyclo[2,2,2]oct-5-endo-2-carboxylate (0.8 mole) instead of tert-butyl5-norbornene-2-carboxylate (0.8 mole), to obtain the following compoundrepresented by Chemical Formula 103. (yield: 38%).

EXAMPLE 18 Synthesis of poly(mono-2-ethyl-2-hydroxymethylbutylbicyclo[2,2,2]oct-5-ene-2,3-dicarboxylate/tert-butylbicyclo[2,2,2]oct-5-endo-2-carboxylate/maleic anhydride)

[0101] The procedure of Example 16 is repeated but using tert-butylbicyclo[2,2,2]oct-5-endo-2-carboxylate (0.8 mole) instead of tert-butyl5-norbornene-2-carboxylate (0.8 mole), to obtain the following compoundrepresented by Chemical Formula 104. (yield: 42%).

EXAMPLE 19 Synthesis of poly(5-norbornene-2-carboxylicacid-3-hydroxyethylcarboxylate/tert-butyl-5-norbornene-2-carboxylate/maleicanhydride/norbornene)

[0102] In 25 ml of tetrahydrofuran, 5-norbornene-2-carboxylicacid-3-hydroxyethylcarboxylate (10 mmol), maleic anhydride (100 mmol),norbornene (20 mmol), tert-butyl-5-norbornene-2-carboxylate (70 mmol)and AIBN (0.30 g) are dissolved, and the solution is reacted at 65° C.for 10 hours. When the reaction is completed, the reaction mixture ispoured into a solvent for crystallization, such as petroleum ether, toobtain a pure solid, which is then filtered off and dried to give thecompound of Chemical Formula 105. (11.3 g/yield: 42%).

EXAMPLE 20 Synthesis of poly(5-norbornene-2-carboxylicacid-3-hydroxypropylcarboxylate/tert-butyl-5-norbornene-2-carboxylate/maleicanhydride/norbornene)

[0103] The procedure of Example 19 is repeated but using5-norbornene-2-carboxylic acid-3-hydroxypropyl carboxylate as areactant, instead of 5-norbornene-2-carboxylic acid-3-hydroxyethylcarboxylate, to obtain the compound represented by Chemical Formula 106as a colorless solid (11.58 g/yield: 41%).

EXAMPLE 21 Synthesis of poly(5-norbornene-2-carboxylicacid-3-hydroxybutylcarboxylate/tert-butyl-5-norbornene-2-carboxylate/maleicanhydride/norbornene)

[0104] The procedure of Example 19 is repeated but using5-norbornene-2-carboxylic acid-3-hydroxybutyl carboxylate as a reactant,instead of 5-norbornene-2-carboxylic acid-3-hydroxyethyl carboxylate toobtain the compound represented by Chemical Formula 107 as a colorlesssolid (11.36 g/yield: 40%).

EXAMPLE 22 Synthesis of poly(5-norbornene-2-carboxylicacid-3-hydroxypentylcarboxylate/tert-butyl-5-norbornene-2-carboxylate/maleicanhydride/norbornene)

[0105] The procedure of Example 19 is repeated but using5-norbornene-2-carboxylic acid-3-hydroxypentyl carboxylate as areactant, instead of 5-norbornene-2-carboxylic acid-3-hydroxyethylcarboxylate to obtain the compound represented by following ChemicalFormula 108 as a colorless solid (11.7 g/yield: 41%).

EXAMPLE 23 Synthesis of poly(5-norbornene-2-carboxylicacid-3-(2-ethyl-2-hydroxymethyl)butylcarboxylate/tert-butyl-5-norbornene-2-carboxylate/maleicanhydride/norbornene)

[0106] The procedure of Example 19 is repeated but using5-norbornene-2-carboxylic acid-3-(2,2,-diethyl)hydroxypropyl carboxylateas a reactant, instead of 5-norbornene-2-carboxylic acid-3-hydroxyethylcarboxylate to obtain the compound represented by following ChemicalFormula 109 as a colorless solid (27.6 g/yield: 45%).

EXAMPLE 24 Synthesis of poly(5-norbornene-2-carboxylicacid-3-(2,2-dimethyl)hydroxypropylcarboxylate/tert-butyl-5-norbornene-2-carboxylate/maleicanhydride/norbornene)

[0107] The procedure of Example 19 is repeated but using5-norbornene-2-carboxylic acid-3-(2,2,-dimethyl)hydroxypropylcarboxylate as a reactant, instead of 5-norbornene-2-carboxylicacid-3-hydroxyethyl carboxylate to obtain the compound represented byfollowing Chemical Formula 110 as a colorless solid (11.7 g/yield: 43%).

EXAMPLE 25 Synthesis of poly(5-norbornene-2-carboxylicacid-3-(2-hydroxyethoxy)ethylcarboxylate/tert-butyl-5-norbornene-2-carboxylate/maleicanhydride/norbornene)

[0108] The procedure of Example 19 is repeated but using5-norbornene-2-carboxylic acid-3-(2-ethoxy)ethanol carboxylate as areactant, instead of 5-norbornene-2-carboxylic acid-3-hydroxyethylcarboxylate to obtain the compound represented by following ChemicalFormula 111 as a colorless solid (10.9 g/yield: 39%).

EXAMPLE 26 Synthesis of poly(oxabicyclo[2.2.1]hept-5-ene-2-carboxylicacid-3-hydroxyethylcarboxylate/tert-butyl-5-norbornene-2-carboxylate/maleicanhydride/norbornene)

[0109] In 25 ml of tetrahydrofuran,oxabicyclo[2.2.1]oct-5-ene-2-carboxylic acid-3-hydroxyethyl carboxylate(10 mmol), maleic anhydride (100 mmol), norbornene (20 mmol),tert-butyl-5-norbornene-2-carboxylate (70 mmol) and AIBN (0.30 g) aredissolved, and the solution is reacted at 65° C. for 10 hours. After thereaction is completed, the reaction mixture is poured into diethyl etherto obtain a pure solid, which is then dried to give the compoundrepresented by following Chemical Formula 112 (11 g/yield: 41%).

EXAMPLE 27 Synthesis of poly(oxabicyclo[2.2.1]hept-5-ene-2-carboxylicacid-3-hydroxypropyl carboxylate/maleicanhydride/norbornene/tert-butyl-5-norbornene-2-carboxylate)

[0110] The procedure of Example 26 is repeated but usingoxabicyclo[2.2.1]oct-5-ene-2-carboxylic acid-3-hydroxypropyl carboxylateinstead of oxabicyclo[2.2.1]oct-5-ene-2-carboxylic acid-3-hydroxyethylcarboxylate to obtain the compound represented by following ChemicalFormula 113 as a colorless solid (11.3 g/yield: 42%).

EXAMPLE 28 Synthesis of poly(oxabicyclo[2.2.1]hept-5-ene-2-carboxylicacid-3-hydroxybutylcarboxylate/tert-butyl-5-norbornene-2-carboxylate/maleicanhydride/norbornene)

[0111] The procedure of Example 26 is repeated but usingoxabicyclo[2.2.1]oct-5-ene-2-carboxylic acid-3-hydroxybutyl carboxylateinstead of oxabicyclo[2.2.1]oct-5-ene-2-carboxylic acid-3-hydroxyethylcarboxylate to obtain the compound represented by following ChemicalFormula 114 as a colorless solid (11.1 g/yield: 42%).

EXAMPLE 29 Synthesis of poly(oxabicyclo[2.2.1]hept-5-ene-2-carboxylicacid-3-hydroxypentylcarboxylate/tert-butyl-5-norbornene-2-carboxylate/maleicanhydride/norbornene)

[0112] The procedure of Example 26 is repeated but usingoxabicyclo[2.2.1]oct-5-ene-2-carboxylic acid-3-hydroxypentyl carboxylateas a reactant, instead of oxabicyclo[2.2.1]oct-5-ene-2-carboxylicacid-3-hydroxyethyl carboxylate to obtain the compound represented byfollowing Chemical Formula 115 as a colorless solid (10.9 g/yield: 40%).

EXAMPLE 30 Synthesis of poly(oxabicyclo[2.2.1]hept-5-ene-2-carboxylicacid-3-(2.2-diethyl)hydroxypropylcarboxylate/tert-butyl-5-norbornene-2-carboxylate/maleicanhydride/norbornene)

[0113] The procedure of Example 26 is repeated but usingoxabicyclo[2.2.1]oct-5-ene-2-carboxylicacid-3-(2,2-diethyl)hydroxypropyl carboxylate as a reactant, instead ofoxabicyclo[2.2.1]oct-5-ene-2-carboxylic acid-3-hydroxyethyl carboxylateto obtain the compound represented by following Chemical Formula 116 asa colorless solid (12.1 g/yield: 44%).

EXAMPLE 31 Synthesis of poly(oxabicyclo[2.2.1]hept-5-ene-2-carboxylicacid-3-(2,2-dimethyl)hydroxypropylcarboxylate/tert-butyl-5-norbornene-2-carboxylate/maleicanhydride/norbornene)

[0114] The procedure of Example 26 is repeated but usingoxabicyclo[2.2.1]oct-5-ene-2-carboxylicacid-3-(2,2-dimethyl)hydroxypropyl carboxylate as a reactant, instead ofoxabicyclo[2.2.1]oct-5-ene-2-carboxylic acid-3-hydroxyethyl carboxylateto obtain the compound represented by following Chemical Formula 117 asa colorless solid (11.7 g/yield: 43%).

EXAMPLE 32 Synthesis of poly(oxabicyclo[2.2.1]hept-5-ene-2-carboxylicacid-3-(2-ethoxy)ethanolcarboxylate/tert-butyl-5-norbornene-2-carboxylate/maleicanhydride/norbornene)

[0115] The procedure of Example 26 is repeated but usingoxabicyclo[2.2.1]oct-5-ene-2-carboxylic acid-3-(2-ethoxy)ethanolcarboxylate as a reactant, instead ofoxabicyclo[2.2.1]oct-5-ene-2-carboxylic acid-3-hydroxyethyl carboxylateto obtain the compound represented by following Chemical Formula 118 asa colorless solid (10.7 g/yield: 39%).

[0116] In the Examples described above, petroleum ether or diethyl etheris employed as a solvent for crystallization. Alternatively, alcoholssuch as methanol, ethanol and isopropanol may be employed.

[0117] Preparation of Photoresist Composition and Formation ofPhotoresist Pattern

EXAMPLE 33

[0118] 10 g of poly(5-norbornene-2-carboxylicacid-3-(2,2-diethyl)-hydroxypropyl carboxylate/tert-butyl5-norbornene-2-carboxylate/maleic anhydride ) obtained from the Example15 is dissolved in 40 g of 3-methoxymethyl propionate, andtriphenylsulfonium triflate or dibutyl naphthyl sulfoniumtriflate(0.01-1 g) is added thereto as a photoacid generator. Afterstirring, the resultant mixture is filtered through a 0.10 μm filter toobtain a photoresist composition. The photoresist composition thusobtained is coated in about 0.3 μm thickness on a surface, and exposedto light by using 193 nm of ArF light source. Then the photoresist ispost-baked, and the semiconductor element is impregnated in 2.38%aqueous tetramethylammonium hydroxide (TMAH) solution to be developedand thus 0.13 μm L/S pattern is obtained.

EXAMPLE 34

[0119] The procedure of Example 33 is repeated but using the photoresistcopolymer obtained from the Example 16 instead of that obtained from theExample 15 and thus a 0.13 μm L/S pattern is obtained.

EXAMPLE 35

[0120] The copolymer obtained from Example 19 (10 g) andtriphenylsulfonium triflate (0.12 g) as a photoacid generator aredissolved in ethyl 3-ethoxypropionate solvent (60 g), and the resultantmixture is filtered through a 0.1 μm filter to prepare a photoresistsolution. The photoresist solution thus prepared is spin-coated on asilicon wafer, and soft-baked at 110° C. for 90 seconds. After baking,the wafer is irradiated with light exposure energy of 0.1 to 10 mJ/cm²by using an ArF laser exposer, and the wafer is post-baked again at 110°C. for 90 seconds. When the post-baking is completed, it is developed in2.38 w % aqueous TMAH (tetramethylammonium hydroxide) solution for 40seconds, to obtain a 0.11 μm L/S pattern.

EXAMPLE 36

[0121] The procedure according to Example 35 is repeated but using thesame amount of the copolymer obtained from Example 20 instead of thecopolymer of Example 19, to obtain 0.13 μm L/S pattern.

EXAMPLE 37

[0122] The procedure according to Example 35 is repeated but using thesame amount of the copolymer obtained from Example 21 instead of thecopolymer of Example 19, to obtain a 0.13 μm L/S pattern.

EXAMPLE 38

[0123] The procedure according to Example 35 is repeated but using thesame amount of the copolymer obtained from Example 22 instead of thecopolymer of Example 19, to obtain a 0.13 μm L/S pattern.

EXAMPLE 39

[0124] The procedure according to Example 35 is repeated but using thesame amount of the copolymer obtained from Example 23 instead of thecopolymer of Example 19, to obtain a 0.13 μm L/S pattern.

EXAMPLE 40

[0125] The procedure according to Example 35 is repeated but using thesame amount of the copolymer obtained from Example 24 instead of thecopolymer of Example 19, to obtain a 0.13 μm L/S pattern.

EXAMPLE 41

[0126] The procedure according to Example 35 is repeated but using thesame amount of the copolymer obtained from Example 25 instead of thecopolymer of Example 19, to obtain a 0.12 μm L/S pattern.

EXAMPLE 42

[0127] The procedure according to Example 35 is repeated but using thesame amount of the copolymer obtained from Example 26 instead of thecopolymer of Example 19, to obtain a 0.12 μm L/S pattern.

EXAMPLE 43

[0128] The procedure according to Example 35 is repeated but using thesame amount of the copolymer obtained from Example 27 instead of thecopolymer of Example 19, to obtain a 0.11 μm L/S pattern.

EXAMPLE 44

[0129] The procedure according to Example 35 is repeated but using thesame amount of the copolymer obtained from Example 28 instead of thecopolymer of Example 19, to obtain a 0.13 μm L/S pattern.

EXAMPLE 45

[0130] The procedure according to Example 35 is repeated but using thesame amount of the copolymer obtained from Example 29 instead of thecopolymer of Example 19, to obtain a 0.13 μm L/S pattern.

EXAMPLE 46

[0131] The procedure according to Example 35 is repeated but using thesame amount of the copolymer obtained from Example 30 instead of thecopolymer of Example 19, to obtain a 0.12 μm L/S pattern.

EXAMPLE 47

[0132] The procedure according to Example 35 is repeated but using thesame amount of the copolymer obtained from Example 31 instead of thecopolymer of Example 19, to obtain a 0.13 μm L/S pattern.

EXAMPLE 48

[0133] The procedure according to Example 35 is repeated but using thesame amount of the copolymer obtained from Example 32 instead of thecopolymer of Example 19, to obtain a 0.13 μm L/S pattern.

What is claimed is:
 1. A photoresist monomer represented by followingChemical formula 1:

wherein, R is substituted or non-substituted linear or branched (C₁-C₁₀)alkyl, substituted or non-substituted (C₁-C₁₀) ether, substituted ornon-substituted (C₁-C₁₀) ester, or substituted or non-substituted(C₁-C₁₀) ketone; X and Y are independently CH₂, CH₂CH₂, oxygen orsulfur; and i is 0 or an integer of 1 to
 2. 2. A photoresist monomeraccording to claim 1, wherein said R is represented by the followingChemical Formula 1a.

wherein, Z is carbon or oxygen; R₁ and R₂ are independently H or an(C₁-C₅) alkyl; and m and n are independently 0 or an integer of 1 to 5.3. A photoresist monomer according to claim 1, wherein said i is zero.4. A photoresist monomer according to claim 1, wherein said photoresistmonomer is represented by the following Chemical Formula
 2.

wherein, Y is CH₂, CH₂CH₂, oxygen or sulfur; Z is carbon or oxygen; R₁and R₂ are independently H or an (C₁-C₅) alkyl; and m and n areindependently 0 or an integer of 1 to
 5. 5. A photoresist monomeraccording to claim 1, wherein said photoresist monomer is selected fromthe group consisting of 5-norbornene-2-carboxylic acid-3-hydroxyethylcarboxylate; 5-norbornene-2-carboxylic acid-3-hydroxypropyl carboxylate;5-norbornene-2-carboxylic acid-3-hydroxybutyl carboxylate;5-norbornene-2-carboxylic acid-3-hydroxypentyl carboxylate;5-norbornene-2-carboxylic acid-3-(2-ethyl-hydroxymethyl)butylcarboxylate; 5-norbornene-2-carboxylic acid-3-(2,2-dimethylhydroxypropyl carboxylate; 5-norbornene-2-carboxylic acid-3-(2-hydroxyethoxy)ethyl carboxylate;oxabicyclo[2.2.1]-hept-5-ene-2-carboxylic acid-3-hydroxyethylcarboxylate; oxabicyclo[2.2.1]hept-5-ene-2-carboxylicacid-3-hydroxypropyl carboxylate;oxabicyclo[2.2.1]hept-5-ene-2-carboxylic acid-3-hydroxybutylcarboxylate; oxabicyclo[2.2.1]hept-5-ene-2-carboxylicacid-3-hydroxypentyl carboxylate;oxabicyclo[2.2.1]hept-5-ene-2-carboxylicacid-3-(2-ethyl-2-hydroxymethyl)butyl carboxylate;oxabicyclo[2.2.1]hept-5-ene-2-carboxylicacid-3-(2,2-dimethyl)hydroxypropyl carboxylate; andoxabicyclo[2.2.1]hept-5-ene-2-carboxylic acid-3-(2-hydroxyethoxy)ethylcarboxylate.
 6. A method for synthesizing a photoresist monomerrepresented by the following Chemical Formula 1 comprising; (a)dissolving a di-alcohol compound in an organic solvent; (a) adding anacid catalyst or a base to the resultant solution with stirring; and (a)adding an anhydride compound to the resultant solution to obtain acompound of Formula 1:

 wherein, R is substituted or non-substituted linear or branched(C₁-C₁₀) alkyl, substituted or non-substituted (C₁-C₁₀) ether,substituted or non-substituted (C₁-C₁₀) ester, or substituted ornon-substituted (C₁-C₁₀) ketone; X and Y are independently CH₂, CH₂CH₂,oxygen or sulfur; and i is 0 or an integer of 1 to
 2. 7. A methodaccording to the claim 6, wherein said anhydride compound is5-norbornene-2,3-dicarboxylic anhydride orexo-3,6-epoxy-1,2,3,6-tetrahydrophthalic anhydride.
 8. A methodaccording to the claim 6, wherein said di-alcohol compound is selectedfrom the group consisting of ethylene glycol, 1,3-propanediol,1,4-butanediol, 1,5-pentanediol, 2,2-diethyl-1,3-propanediol,2,2-dimethyl-1,3-propanediol and diethylene glycol.
 9. A methodaccording to the claim 6, wherein said organic solvent is selected fromthe group consisting of tetrahydrofuran, dimethylformamide, dioxane,benzene and toluene.
 10. A method according to the claim 6, wherein saidbase is selected from the group consisting of NaH, KH, CaH₂, Na₂CO₃ andLDA (lithium diisopropylamide).
 11. A method according to the claim 6,wherein said acid is selected from the group consisting of sulfuricacid, acetic acid and nitric acid.
 12. A method for synthesizing thephotoresist monomer represented by Chemical Formula 2 below, comprising;(a) reacting a maleic anhydride and a di-alcohol compound in thepresence of an acid catalyst, as shown in Reaction Scheme 1 below; and(a) performing a Diels-Alder reaction with the resultant product, asshown in Reaction Scheme 2 below:

 wherein, Y is CH₂, CH₂CH₂, oxygen or sulfur; Z is carbon or oxygen; R₁and R₂ are independently H or an (C₁-C₅) alkyl; and m and n areindependently 0 or an integer of 1 to
 5. 13. A photoresist polymercomprising at least one monomer represented by the Chemical Formula 1below:

wherein, R is substituted or non-substituted linear or branched (C₁-C₁₀)alkyl, substituted or non-substituted (C₁-C₁₀) ether, substituted ornon-substituted (C₁-C₁₀) ester, or substituted or non-substituted(C₁-C₁₀) ketone; X and Y are independently CH₂, CH₂CH₂, oxygen orsulfur; and i is 0 or an integer of 1 to
 2. 14. A photoresist polymeraccording to claim 13 further comprising a second comonomer representedby the Chemical Formula 3:

wherein, V and W are independently CH₂, CH₂CH₂, oxygen or sulfur; R* isan acid-reactable group; and j is 0or an integer of 1to
 2. 15. Aphotoresist copolymer according to the claim 14, wherein said R* istert-butyl, 2-tetrahydrofuranyl, 2-tetrahydropyranyl, 2-ethoxyethyl ort-butoxyethyl.
 16. A photoresist copolymer according to the claim 14,wherein said i=j=0.
 17. A photoresist copolymer according to the claim14 wherein said compound represented by the following Chemical Formula 3is tert-butyl-5-norbornene-2-carboxylate, the compound of followingChemical Formula 3a or the compound of following Chemical Formula 3b:


18. A photoresist copolymer according to the claim 14 further comprisinga polymerization-enhancing monomer selected from the group consisting ofmaleic anhydride and maleimide derivatives.
 19. A photoresist copolymeraccording to the claim 14, said photoresist copolymer further comprisinga spacer material represented by the following Chemical Formula
 4.

wherein, U is CH₂, CH₂CH₂, oxygen or sulfur; and R′ is hydrogen or C₁-C₅alkyl.
 20. A photoresist copolymer according to the claim 14, whereinsaid photoresist copolymer is selected from the group consisting of thefollowing Chemical Formulas 100, 200, 100a and 200a.

wherein, X, Y, V, W and U are independently CH₂, CH₂CH₂, oxygen orsulfur; R is substituted or non-substituted linear or branched (C₁-C₁₀)alkyl, substituted or non-substituted (C₁-C₁₀) ether, substituted ornon-substituted (C₁-C₁₀) ester, or substituted or non-substituted(C₁-C₁₀) ketone; R* is an acid-reactable group; R′ is hydrogen or C₁-C₅alkyl; i and j are independently 0 or an integer of 1 to 2; and a, b, cand d are independently the polymerization ratios of the monomers.
 21. Aphotoresist copolymer according to the claim 14 wherein the averagemolecular weight of said photoresist copolymer is 3,000 to 12,000.
 22. Aphotoresist copolymer according to the claim 14, wherein saidphotoresist copolymer is selected from the group consisting ofpoly(5-norbornene-2-carboxylic acid-3-(2,2-diethyl)-hydroxypropylcarboxylate/tert-butyl 5-norbornene-2-carboxylate/maleic anhydride);poly(mono-2-ethyl-2-hydroxymethylbutylbicyclo[2,2,2]oct-5-ene-2,3-dicarboxylate/tert-butyl5-norbornene-2-carboxylate/maleic anhydride);poly(5-norbornene-2-carboxylic acid-3-(2,2-diethyl)-hydroxypropylcarboxylate/tert-butyl bicyclo[2,2,2]oct-5-endo-2-carboxylate/maleicanhydride) poly(mono-2-ethyl-2-hydroxymethylbutylbicyclo[2,2,2]oct-5-ene-2,3-dicarboxylate/tert-butylbicyclo[2,2,2]oct-5-endo-2-carboxylate/maleic anhydride);poly(5-norbornene-2-carboxylic acid-3-hydroxyethylcarboxylate/tert-butyl-5-norbornene-2-carboxylate/maleicanhydride/norbornene); poly(5-norbornene-2-carboxylicacid-3-hydroxypropylcarboxylate/tert-butyl-5-norbornene-2-carboxylate/maleicanhydride/norbornene); poly(5-norbornene-2-carboxylicacid-3-hydroxybutylcarboxylate/tert-butyl-5-norbornene-2-carboxylate/maleicanhydride/norbornene); poly(5-norbornene-2-carboxylicacid-3-hydroxypentylcarboxylate/tert-butyl-5-norbornene-2-carboxylate/maleicanhydride/norbornene); poly(5-norbornene-2-carboxylicacid-3-(2-ethyl-2-hydroxymethyl)butylcarboxylate/tert-butyl-5-norbornene-2-carboxylate/maleicanhydride/norbornene); poly(5-norbornene-2-carboxylicacid-3-(2,2-dimethyl)hydroxypropylcarboxylate/tert-butyl-5-norbornene-2-carboxylate/maleicanhydride/norbornene); poly(5-norbornene-2-carboxylicacid-3-(2-hydroxyethoxy)ethylcarboxylate/tert-butyl-5-norbornene-2-carboxylate/maleicanhydride/norbornene); poly(oxabicyclo[2.2.1]hept-5-ene-2-carboxylicacid-3-hydroxyethylcarboxylate/tert-butyl-5-norbornene-2-carboxylate/maleicanhydride/norbornene); poly(oxabicyclo [2.2.1]hept-5-ene-2-carboxylicacid-3-hydroxypropyl carboxylate/maleicanhydride/norbornene/tert-butyl-5-norbornene-2-carboxylate);poly(oxabicyclo[2.2.1]hept-5-ene-2-carboxylic acid-3-hydroxybutylcarboxylate/tert-butyl-5-norbornene-2-carboxylate/maleicanhydride/norbornene); poly(oxabicyclo[2.2.1]hept-5-ene-2-carboxylicacid-3-hydroxypentylcarboxylate/tert-butyl-5-norbornene-2-carboxylate/maleicanhydride/norbornene); poly(oxabicyclo[2.2.1]hept-5-ene-2-carboxylicacid-3-(2,2-diethyl)hydroxypropylcarboxylate/tert-butyl-5-norbornene-2-carboxylate/maleicanhydride/norbornene); poly(oxabicyclo[2.2.1]hept-5-ene-2-carboxylicacid-3-(2,2-dimethyl)hydroxypropylcarboxylate/tert-butyl-5-norbornene-2-carboxylate/maleicanhydride/norbornene); and poly(oxabicyclo[2.2.1]hept-5-ene-2-carboxylicacid-3-(2-ethoxy)ethanolcarboxylate/tert-butyl-5-norbornene-2-carboxylate/maleicanhydride/norbornene).
 23. A method for synthesizing a photoresistcopolymer, which comprises: (a) dissolving in an organic solvent (i) acompound represented by the following Chemical Formula 1, (ii) acompound represented by the following Chemical Formula 3 and (iii) atleast one of maleic anhydride and maleimide derivatives; and (b) addinga polymerization initiator to the resultant solution to induce apolymerization reaction.

 wherein, R is substituted or non-substituted linear or branched(C₁-C₁₀) alkyl, substituted or non-substituted (C₁-C₁₀) ether,substituted or non-substituted (C₁-C₁₀) ester, or substituted ornon-substituted (C₁-C₁) ketone; X and Y are independently CH₂, CH₂CH₂,oxygen or sulfur; and i is 0 or an integer of 1 to
 2.

 wherein, V and W are independently CH₂, CH₂CH₂, oxygen or sulfur; R* isan acid-reactable group; and j is 0 or an integer of 1 to
 2. 24. Amethod according to the claim 23 wherein said organic solvent isselected from the group consisting of tetrahydrofuran,dimethylformamide, dimethyl sulfoxide, dioxane, methyl ethyl ketone,benzene, toluene and xylene.
 25. A method according to the claim 23,wherein said polymerization initiator is selected from the groupconsisting of 2,2-azobisisobutyronitile (AIBN), acetyl peroxide, laurylperoxide and tert-butyl peroxide.
 26. A method according to the claim23, wherein said (a) step further comprises adding a spacer monomerrepresented by the following Chemical Formula 4 into the organicsolvent.

wherein, U is CH₂, CH₂CH₂, oxygen or sulfur; and R′ is hydrogen or C₁-C₅alkyl.
 27. A method of synthesizing a photoresist copolymer, whichcomprises: (a) dissolving in an organic solvent (i) a compoundrepresented by the following Chemical Formula 1 and (ii) a compoundrepresented by the following Chemical Formula 3, and (b) adding a metalcatalyst to the resultant solution to induce polymerization reaction.

 wherein, R is substituted or non-substituted linear or branched(C₁-C₁₀) alkyl, substituted or non-substituted (C₁-C₁₀) ether,substituted or non-substituted (C₁-C₁₀) ester, or substituted ornon-substituted (C₁-C₁₀) ketone; X and Y are independently CH₂, CH₂CH₂,oxygen or sulfur; and i is 0 or an integer of 1 to
 2.

 wherein, V and W are independently CH₂, CH₂CH₂, oxygen or sulfur; R* isan acid-reactable group; and j is 0 or an integer of 1 to
 2. 28. Amethod according to the claim 27, wherein said (a) step furthercomprises the step of adding a spacer monomer represented by thefollowing Chemical Formula 4 to the organic solvent.

wherein, U is CH₂, CH₂CH₂, oxygen or sulfur; and R′ is hydrogen or C₁-C₅alkyl.
 29. A photoresist composition comprising (i) a photoresistcopolymer of claim 13, 14, 18 or 19; (ii) a photoacid generator and(iii) an organic solvent.
 30. A photoresist composition according toclaim 29, wherein said photoacid generator is sulfide or onium typecompounds.
 31. A photoresist composition according to claim 29, whereinsaid photoacid generator is selected from the group consisting ofdiphenyl iodide hexafluorophosphate, diphenyl iodide hexafluoroarsenate,diphenyliodide hexafluoroantimonate, diphenyl p-methoxyphenyl triflate,diphenyl p-toluenyl triflate, diphenyl p-isobutylphenyl triflate,diphenyl p-tert-butylphenyl triflate, triphenylsulfoniumhexafluorophosphate, triphenylsulfonium hexafluoroarsenate,triphenylsulfonium hexafluoroantimonate, triphenylsulfonium triflate anddibutylnaphthylsulfonium triflate.
 32. A photoresist compositionaccording to claim 29, wherein said organic solvent is selected from thegroup consisting of ethyl 3-ethoxypriopionate, methyl3-methoxypropionate, cyclohexanone and propyleneglycol methyletheracetate.
 33. A process for forming a photoresist pattern, said processcomprising (a) coating a photoresist composition of claim 29 on asemiconductor substrate to form a photoresist film; (b) exposing thephotoresist film using an exposing device; and (c) developing thephotoresist film.
 34. A process according to claim 32, which furthercomprises a step of soft-baking after step (a).
 35. A process accordingto claim 34, wherein the soft-baking is performed at 70-200° C.
 36. Aprocess according to claim 33 which further comprises a step ofpost-baking, after step (b).
 37. A process according to claim 36,wherein the post-baking is performed at 70-200° C.
 38. A processaccording to claim 33, wherein said exposing device employs a lightsource having a wavelength below 250 nm.
 39. A process according toclaim 33, wherein said exposing device employs a light source selectedfrom the group consisting of ArF, KrF, E-beam, ion-beam, VUV(VacuumUltra Violet), EUV and X-ray.
 40. A semiconductor element manufacturedby the process of the claim 33.